Re: C= and internet

From: Nate Dannenberg (
Date: 2001-02-15 07:11:35

> I must ask, what the hell is a IIC/SPI buss?

Both are serial bus interfaces. The format, also called I2C, is more of a
control bus; you send commands and information to other devices along that
bus to tell them what to do with data that is coming over another bus,
perhaps I2S.  I2C comprises two wires, a clock like and a data line.

SPI, I assume, just means Serial Port Interface.

The complemnt to I2C is I2S, which is just a generic serial bus intended
for sending data streams like audio or continuous measurements, where
commands don't really need to be sent along with the data stream.

I2S includes one each of clock and data lines, plus an arbitrary number of
control lines, intended to take the place of the command protocol that
might otherwise be provided by I2C.

The MP3 board I've been trying to design requires the use of the I2C

According to what I've researched about it, it's similar to the RS232
protocol..  Each command has a start signal and a stop signal, and each
byte of data has it's own stop bit as well.  The start/stop signals are
sent by coordinated transitions of both the data and clock lines, into
states that won't happen during the actual data transfer.

The MP3 chip I'm using uses I2S to talk to a DAC for the actual audio
output, and can use another I2S port for the Mp3 stream input (I use the
parallel port method instead).

> If this could be made to work, it would provide a very
> expeditious method of interfacing with a PC or Unix
> network. I can see my C64 under NeworkNeighborhood
> already  ;)

Why all this talk about getting on the net?  It's been done already, both
on stock machines (LUnix, Novaterm 10) and Super-CPU accellerated machines
(JOS, Wheels/The Wave).

What we need, in my opinion, is not a new TCP/IP stack, those already
exist.  We don't need PPP, we already have it.  What we need is an
Ethernet card for the C64/128.  RS232 cards like Swiftlink and Turbo232 do
work, but they are slow and cause a lot of processor overhead (due to

The HART Cartridge (Hatronics, uses a 16550 UART) is better since it's
primary chip requires one fourth as much interrupt usage.  In fact I
wouldn't be surprised if it were possible to extend this to use modern
versions of the 16x50 that have even larger buffers (one model has 64

Ethernet would be the best thing, since it's more widely accepted than
RS232 in high-speed situations (cablemodem, anyone?).

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